In transporting various types of cargo within railroad freight cars, trucks or other vehicles, invariably, the horizontal dimension of the loads do not completely fill the interior space within the vehicle. Thus, there are voids usually left between the various loads whether it is between the load itself or between the load and the walls of the vehicle. If this void is left unattended, the load or cargo during movement of the vehicle will shift and in some cases cause considerable damage to the load and/or vehicle.
In the past, it has been common when shipping a large volume of materials to unitize these materials on pallets or other support devices. The boxes, bags or loose objects which are intended to be shipped are stacked to a reasonable height and the goods are either banded together to secure them as a unit or they are wrapped, usually with a plastic sheet material to hold the load in a unitized or palletized configuration. As previously stated, even though there may be an attempt to size the palletized units to fit within the cargo bay of the rail car, ship, truck or other vehicle, variations in the dimensions of the loads cause voids or spaces to occur.
In the past, shippers have been generally successful in stuffing or forcing packing or other loose material between the load units to prevent them from shifting or moving. Invariably, this is a very cumbersome and unacceptable way to ship various materials since the packing materials have to be handled and stored between use. In addition, the packing usually is substantially loose and thus, extremely hard to handle and control, thus adding cost to the shipment.
Another way of solving this problem is the use of air bags which can be inserted between the various palletized or unitized loads and inflated. These work very well as long as the air bags are not punctured and hold their pressure. However, during transit, if the bags deflate, then the loads are free to move with possible consequential damage. In addition, the air bags are very expensive to manufacture especially if they have sufficient strength and rigidity to prevent puncture and yet be light enough to be easily handled. Thus, even though the bags can be manufactured to remain substantially inflated, they became so heavy that they are difficult to handle and in addition, are quite expensive to manufacture.
Others over a period of years have tried to use folded, corrugated cardboard as a dunnage device or void filler. These early devices were merely folded layers of cardboard inserted to fill the void between the elements of the load. Later attempts were made to use folded boxes which could be unfolded or expanded when used and thus, occupy a greater space and fill the void more efficiently. More recently, however, various types of void fillers have been utilized which provide arrangements for folding the sheet material into a tubular configuration or a U-shaped configuration with various slotted cross members used to hold the filler material in position. Flanges have been attached to the top of the void filler to support the mass between the various loads whether on the top or in between various layers of the load.
In most cases, these devices have been designed so that they can be reused and readily stored. This means that they can be disassembled or taken apart or folded so that they can be reduced to a relatively small or flat object taking up a minimal amount of storage space.
All of the devices which have been utilized up to the present time have various known problems or flaws which can be primarily related to their complexity as well as their expense in manufacture. What is really needed is a void filler which will provide the substantial strength and rigidity necessary to support the loads while in use and yet, will be very thin, lightweight and inexpensive to manufacture. This is the primary object of the present invention.